Cryo-EM map of the WT KdpFABC complex in the E1-P_ADP conformation, under turnover conditionsCryo-EM map of the WT KdpFABC complex in the E1-P_ADP conformation, under turnover conditions

Structural highlights

7zrk is a 4 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:, , , ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

KDPA_ECOLI Part of the high-affinity ATP-driven potassium transport (or Kdp) system, which catalyzes the hydrolysis of ATP coupled with the electrogenic transport of potassium into the cytoplasm (PubMed:2849541, PubMed:8499455, PubMed:23930894). This subunit binds and transports the potassium across the cytoplasmic membrane (PubMed:7896809).[1] [2] [3] [4]

Publication Abstract from PubMed

KdpFABC is a high-affinity prokaryotic K<sup>+</sup> uptake system that forms a functional chimera between a channel-like subunit (KdpA) and a P-type ATPase (KdpB). At high K<sup>+</sup> levels, KdpFABC needs to be inhibited to prevent excessive K<sup>+</sup> accumulation to the point of toxicity. This is achieved by a phosphorylation of the serine residue in the TGES<sub>162</sub> motif in the A domain of the pump subunit KdpB (KdpB<sub>S162-P</sub>). Here, we explore the structural basis of inhibition by KdpB<sub>S162</sub> phosphorylation by determining the conformational landscape of KdpFABC under inhibiting and non-inhibiting conditions. Under turnover conditions, we identified a new inhibited KdpFABC state that we termed E1P tight, which is not part of the canonical Post-Albers transport cycle of P-type ATPases. It likely represents the biochemically described stalled E1P state adopted by KdpFABC upon KdpB<sub>S162</sub> phosphorylation. The E1P tight state exhibits a compact fold of the three cytoplasmic domains and is likely adopted when the transition from high-energy E1P states to E2P states is unsuccessful. This study represents a structural characterization of a biologically relevant off-cycle state in the P-type ATPase family and supports the emerging discussion of P-type ATPase regulation by such states.

Inhibited KdpFABC transitions into an E1 off-cycle state.,Silberberg JM, Stock C, Hielkema L, Corey RA, Rheinberger J, Wunnicke D, Dubach VRA, Stansfeld PJ, Hanelt I, Paulino C Elife. 2022 Oct 18;11. pii: 80988. doi: 10.7554/eLife.80988. PMID:36255052[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Damnjanovic B, Weber A, Potschies M, Greie JC, Apell HJ. Mechanistic analysis of the pump cycle of the KdpFABC P-type ATPase. Biochemistry. 2013 Aug 20;52(33):5563-76. doi: 10.1021/bi400729e. Epub 2013 Aug, 9. PMID:23930894 doi:http://dx.doi.org/10.1021/bi400729e
  2. Siebers A, Altendorf K. The K+-translocating Kdp-ATPase from Escherichia coli. Purification, enzymatic properties and production of complex- and subunit-specific antisera. Eur J Biochem. 1988 Dec 1;178(1):131-40. PMID:2849541
  3. Buurman ET, Kim KT, Epstein W. Genetic evidence for two sequentially occupied K+ binding sites in the Kdp transport ATPase. J Biol Chem. 1995 Mar 24;270(12):6678-85. PMID:7896809
  4. Kollmann R, Altendorf K. ATP-driven potassium transport in right-side-out membrane vesicles via the Kdp system of Escherichia coli. Biochim Biophys Acta. 1993 Jun 10;1143(1):62-6. PMID:8499455
  5. Silberberg JM, Stock C, Hielkema L, Corey RA, Rheinberger J, Wunnicke D, Dubach VRA, Stansfeld PJ, Hanelt I, Paulino C. Inhibited KdpFABC transitions into an E1 off-cycle state. Elife. 2022 Oct 18;11. pii: 80988. doi: 10.7554/eLife.80988. PMID:36255052 doi:http://dx.doi.org/10.7554/eLife.80988

7zrk, resolution 3.10Å

Drag the structure with the mouse to rotate

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA